**2.3 Wudalianchi ice cave**

There are two ice caves at Wudalianchi National Geological Park (48.647°, 126.25°, 400 m asl), Heilongjiang Province: one is Bailong (means white dragon; also named Dixiabinghe) ice cave, and another is Shuijinggong (means crystal palace) ice cave.

We conducted simple field work on Bailong ice cave in August 2012. The host rock is basalt. Dense fractures developed near the entrance. Basaltic pillars can be seen within the cave. The farthest distance we can reach is about 270 m from

#### **Figure 2.**

*The space and interior of Zibaishan ice cave (modified from [23]). (a) The geometry and temperature profile, (b) ice cone and ice stalactites, (c) ice stalactites.*

#### **Figure 3.**

*Top view (a) and geological radar profile (b) of Bailong ice cave at Wudalianchi National Geological Park (modified from [24]).*

**89**

*A Review of Chinese Ice Caves*

Shuijinggong ice cave.

**3. Formation of cave**

**3.1 Limestone as the host rock**

**3.2 Basalt as the host rock**

type is tension rupture.

cave.

*DOI: http://dx.doi.org/10.5772/intechopen.89178*

the entrance of the ice cave. Wang and Zhu measured the geometry and basaltic fracture of Bailong ice cave by applying geological radar (the antenna frequency is 40 MHz) [24] (**Figure 3**). From the radar profile (**Figure 3b**), we can see that seven large fractures with the same dip direction were developed above the ice

Bailong ice cave was not a pure natural ice cave, but ice blocks were moved into the cave to decorate it, and thus its natural conditions were destroyed. The temperature in the ice cave was about −2°C in August 2012. Shuijinggong ice cave is much smaller than Bailong ice cave but with more man-made ice block which was used to decorate it. Therefore, it is difficult to obtain any natural information from

Caves must be developed before the formation of their internal ice. Cave geometry mainly depended on the lithology of their wall rocks. Two types of lithology

The host rock of Ningwu ice cave and Zibaishan ice cave mainly consists of limestone. Limestone is composed of calcium carbonate which is an unsteady material and could be readily dissolved. Limestone areas could become karst landform under wet and warm climate in the geological period. The limestone cave developed predominantly in the perpendicular direction, for example, Ningwu ice cave and Zibaishan ice cave. Generally, the karst region is not suitable for ice preservation. Ice preservation in karst cave may indicate the climate change from warm to cold

Basaltic caves (often as tubes) were formed in the process of the viscous lava flow, for example, Wudalianchi ice cave. Mechanical stability of lava tubes depends on their size (diameter), buried depth, and geometry in the cooling period. We conducted a series of two-dimensional thermo-elastic finite element calculations to

**Figure 4** shows the principle stress distributions around a lava tube of diameter 10 m at the last computing time step. It can be seen from **Figure 4a** that the largest maximum principal stress is at the top and bottom sides of the lava tube, and it is tensile stress. The left and right sides are also tensile stresses, but the magnitude is much smaller. **Figure 4b** is the minimum principal stress distribution. Obviously, the minimum principal stress of the upper and lower sides of the lava tube is tensile stress, while that of the left and right sides is compressive stress, and the magnitude of the stress around the lava tube is equal. These modeling results reveal that the most vulnerable place of the lava tube is on the top and bottom, and the rupture

We investigated three controlling factors (diameter, depth, and geometry) of lava tubes in the cooling period by FEM method, and the modeling results were illustrated in **Figure 5**. At the last time step, maximum principal stress of **Figure 5a** (normal lava tube) is smaller than that of **Figure 5b** (bigger lava tube), implying bigger lava tubes were easier ruptured. Similarly, lave tubes with larger buried

globally or the presence of incomprehensible cooling mechanisms locally.

were involved in these three ice caves: limestone and basalt.

estimate the effects of these three controlling factors [25].

#### *A Review of Chinese Ice Caves DOI: http://dx.doi.org/10.5772/intechopen.89178*

the entrance of the ice cave. Wang and Zhu measured the geometry and basaltic fracture of Bailong ice cave by applying geological radar (the antenna frequency is 40 MHz) [24] (**Figure 3**). From the radar profile (**Figure 3b**), we can see that seven large fractures with the same dip direction were developed above the ice cave.

Bailong ice cave was not a pure natural ice cave, but ice blocks were moved into the cave to decorate it, and thus its natural conditions were destroyed. The temperature in the ice cave was about −2°C in August 2012. Shuijinggong ice cave is much smaller than Bailong ice cave but with more man-made ice block which was used to decorate it. Therefore, it is difficult to obtain any natural information from Shuijinggong ice cave.
